CN113908074A

CN113908074A - Nicotinamide for inducing antimicrobial peptide production

Info

Publication number: CN113908074A
Application number: CN202111170332.0A
Authority: CN
Inventors: A·马祖姆达; M·S·马塔帕蒂; B·帕兰伊萨米; R·萨姆帕特库马; J·K·蒂瓦里
Original assignee: Unilever IP Holdings BV
Current assignee: Unilever IP Holdings BV
Priority date: 2014-05-12
Filing date: 2014-05-12
Publication date: 2022-01-11
Also published as: ZA201607105B; EA201692284A1; EA031758B1; MX2016014760A; WO2015172801A1; BR112016024400A2; PH12016502047A1; JP2017515829A; CN106413680A; JP6446065B2

Abstract

The present invention relates to a novel use of nicotinamide for triggering the production of AMPs (antimicrobial peptides) on the skin. This can be used to improve the immunity of the skin, scalp and oral cavity to microbial attack.

Description

Nicotinamide for inducing antimicrobial peptide production

The application is a divisional application of an invention patent application, the application date of the parent application is 2014, 5, 12, and the application number is 201480078798.X (PCT/EP2014/059590), and the invention name is "nicotinamide for inducing the generation of antimicrobial peptide".

Technical Field

Background

Skin is the primary line of defense in protecting the human body from pathogens (e.g., viruses and bacteria). As a first defense organ, skin tissue always remains in constant contact with the environment, and therefore it must face and address threats and challenges from invading pathogens. The exposed skin surface is not only challenged by pathogenic foreign bacteria, but also remains in contact with and interacts with resident commensal bacteria. Despite all these challenges from foreign and commensal microorganisms, healthy skin remains free of infection and the number of resident microbial communities remains constant. Because the skin has a complex defense strategy, this balance of interactions between skin tissue and microorganisms is maintained, and antimicrobial peptides (AMPs) constitute an important part of this defense strategy.

AMPs form part of the skin's own defense system. AMPs were initially discovered in insects and animals, and since their initial discovery, AMPs were considered promising antimicrobial agents. AMPs are ubiquitous in nature, and they typically exhibit a broad spectrum of activity against invading bacteria, fungi, enveloped viruses and parasites (Braff and Gallo, 2006). AMPs are generally short peptides, and approximately 90 different AMPs have been reported in humans. AMPs generally have two main physical characteristics, which are: a) cationic charge, and b) a significant proportion of hydrophobic residues. The cationic charge of the AMP increases selectivity for negatively charged microbial cell plasma membranes, while the hydrophobicity facilitates interaction with the cell membranes of the microbial species.

The present inventors have been working on providing hygiene benefits to consumers by increasing AMP levels in the skin. They wish to provide this by using natural molecules which the consumer feels more skin friendly and thus less irritating (hash). To achieve this goal, various actives were tested and after extensive studies it was found that use of niacinamide or vitamin B3 increased the AMP levels on the skin.

Niacinamide or vitamin B3 is a well known skin lightening active used in several skin care products. Niacinamide has also been reported to have various other properties such as prevention of cellulite, treatment of skin irritation, and for improving water absorption on skin (reported in patent publications EP1063963, EP1063994, EP1063965, and the like). Nicotinamide is also used in the treatment of a number of inflammatory skin conditions such as acne vulgaris, psoriasis and atopic dermatitis (Niren, N.M. (2006) pharmacological domains of inflammatory skin conditions: a review. cultures 77: 11-16.).

WO 11133692(Cedars-Sinai Medical Centre) discloses the important role of C/EBPe in the innate immune response against pathogens. In particular, it has been shown that in the absence of functional C/EBPe, mice are severely impaired in their ability to clear staphylococcus aureus infections. Neutrophils are particularly affected and susceptibility to staphylococcus aureus can be modulated by treatment with interferon-gamma (IFN- →). Importantly, increased C/EBPe activity (either by inducing C/EBPe overexpression or by applying niacinamide or its analogs, derivatives or salts) significantly increases the immune killing of staphylococcus aureus and results in remission of the infection.

The present inventors have found that when niacinamide is applied to the skin (which may be the skin itself or the scalp or oral cavity), the active induces the production of AMP, which is known to be an important step in improving the immunity of the skin against microbial attack. Thus, the consumer gains the benefit of protecting the skin against pathogens that may attack the skin in the future by applying a composition comprising niacinamide.

Summary of The Invention

The present invention provides the use of nicotinamide for inducing secretion of antimicrobial peptides (AMPs) when applied on the outer surface of the human body.

Thus, also provided is nicotinamide for prophylactically inducing secretion of antimicrobial peptides (AMPs) when applied on the outer surface of the human body.

Further, the present invention provides a method of providing protection to the scalp by way of inducing secretion of antimicrobial peptides (AMPs) comprising the step of applying niacinamide to the individual's hair/scalp.

Detailed Description

These and other aspects, features and advantages will become apparent to those of ordinary skill in the art upon review of the following detailed description and appended claims. For the avoidance of doubt, any feature of one aspect of the invention may be used in any other aspect of the invention. The word "comprising" is intended to mean "including", but not necessarily "consisting of … …" or "consisting of … …". In other words, the enumerated steps or options need not be exhaustive. It is to be noted that the examples given in the following description are intended to illustrate the present invention and are not intended to limit the present invention to these examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating materials or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about". Numerical ranges expressed in "x to y" format are understood to include x and y. When multiple preferred ranges are described in the format of "x to y" for a particular feature, it is to be understood that all ranges combining the different endpoints are also contemplated.

As used herein, "skin" is intended to include the external surfaces of mammals, especially humans, including the skin, scalp, hair and oral cavity. The use may be by incorporating niacinamide into leave-on or rinse-off products, including any product applied to the human body (primarily to whiten the skin, and also to improve appearance, cleansing, odor control, or general aesthetics). The use is preferably by incorporation into leave-on compositions. The composition may be in the form of a liquid, lotion, cream, foam, scrub, gel, soap bar or toner, or applied using a device or via a mask, cotton pad (pad) or patch. Non-limiting examples of such compositions include leave-on skin lotions and creams, shampoos, conditioners, body washes, soaps, antiperspirants, deodorants, depilatories, lipsticks, foundations, mascaras, sunless tanning products, and sunscreen lotions.

Niacinamide has the structure given below:

niacinamide for use in the present invention preferably induces secretion of AMPs by keratinocytes. The AMPs thus secreted provide an improvement in immunity to the external surface of the body. The external surface includes the skin, scalp or oral cavity.

It has been found by the present invention that niacinamide activates keratinocytes, which are the major cells in the epidermis of the skin, to provide the benefits of the present invention, i.e., to induce secretion of antimicrobial peptides (AMPs). This results in niacinamide enhancing the protective barrier against pathogens. Niacinamide thus protects the body from infection by enhancing the body's own defenses. In other words, the active substance prepares the body surface for germ protection. This is advantageous in that it provides long-lasting protection against pathogens (e.g. up to 24 hours of protection).

The compositions in which niacinamide is used according to the invention may comprise the following preferred features. Niacinamide is preferably present at 0.1 to 5%, more preferably 0.5 to 5%, even more preferably 0.5 to 3% and optimally 1.0 to 3.0% by weight of the composition. The composition preferably comprises a cosmetically acceptable base. The cosmetically acceptable base is preferably a cream, lotion, gel or emulsion.

Personal care compositions can be prepared using different cosmetically acceptable emulsifying or non-emulsifying systems and vehicles. Preferred cosmetically acceptable bases comprise 1 to 25% fatty acids. A further preferred aspect provides a soap comprising 0.1 to 10%. A highly suitable base is a cream. Vanishing creams are especially preferred. Vanishing cream bases typically comprise 5 to 25% by weight fatty acid and 0.1 to 10% by weight soap. Vanishing cream bases provide a highly appreciated matte feel to the skin. C₁₂To C₂₀Fatty acids are especially preferred in vanishing cream bases, and even more preferred is C₁₄To C₁₈A fatty acid. The most preferred fatty acid is stearic acid. The fatty acid may also be a mixture of palmitic and stearic acids.More preferably, the fatty acids in the composition are present in an amount of 5 to 20% by weight of the composition. The soap in the vanishing cream base comprises an alkali metal salt of a fatty acid, such as a sodium or potassium salt, most preferably potassium stearate. The soap in the vanishing cream base is typically present in an amount of 0.1 to 10% by weight, more preferably 0.1 to 3% by weight of the composition. When formulated as a vanishing cream, the personal care composition preferably comprises from 60 to 85 wt%, more preferably from 65 to 80 wt% water. Water is typically present in many compositions prepared according to the present invention and is typically present at 40 to 85% by weight of the composition.

The compositions of the present invention may comprise other optional ingredients, such as skin lightening agents, and one or more UV sunscreens. The composition according to the invention may also comprise other diluents. The diluent acts as a dispersant or carrier for other materials present in the composition to facilitate its distribution when the composition is applied to the skin. Diluents other than water may include liquid or solid emollients, solvents, humectants, thickeners and powders.

The composition may optionally be delivered as a deodorant. By deodorant is meant a product in a stick, roll-on or propellant vehicle for personal deodorant benefits, such as application to the underarm area, which may or may not contain an antiperspirant active.

Deodorant compositions can be generally in solid, soft solid, gel, cream and liquid form and are dispensed using an applicator (applicator) adapted to the physical characteristics of the composition.

The composition may contain a wide range of other optional components. CTFA Cosmetic Ingredient Handbook, second edition, 1992, which is incorporated herein by reference in its entirety, describes a wide variety of non-limiting Cosmetic and pharmaceutical ingredients commonly used in the skin care industry, which are suitable for use in the compositions of the present invention. Examples include: antioxidants, binders, biological additives, buffering agents, colorants, thickeners, polymers, astringents, fragrances, humectants, sunscreens, conditioning agents, exfoliants, pH adjusters, preservatives, natural extracts, essential oils, skin sensates (sensates), skin soothing agents, and skin repair agents.

The composition is formulated in any known form, such as shampoo, leave-on cream, lotion, tonic or essence, more preferably in the form of shampoo, cream or lotion.

Yet another aspect of the present invention relates to a method of providing protection to the scalp by way of inducing secretion of antimicrobial peptides (AMPs) comprising the step of applying niacinamide to the individual's hair/scalp. Nicotinamide is preferably applied in therapeutic amounts to induce secretion of the antimicrobial peptide.

Protection of the scalp from secretion of AMPs preferably results in prolonged protection or longer lasting protection of the scalp against scalp related problems such as dandruff. The use of niacinamide may alternatively provide excellent dandruff control due to enhanced AMP secretion. Furthermore, by this mechanism, excellent dandruff control is imparted to the scalp, and in some cases resistance against repeatedly produced dandruff is imparted to the scalp.

Thus, enhanced AMP secretion due to the application of niacinamide provides enhanced protection/defense, resistance to dandruff, and deep-seated (advanced) nutritional benefits. Persons afflicted with dandruff or dry and itchy scalp may experience the benefits of the present invention.

According to a preferred aspect, the use of nicotinamide by the invention is preferably non-therapeutic.

The invention will now be further described by way of the following non-limiting examples.

Examples

Examples 1 to 6: it was demonstrated that nicotinamide induces the expression of the LL-37 gene without altering psoriatin expression Examples of (1)

The following samples as shown in Table 1 were prepared in order to measure their effect on psoriatin AMP (LL-37) expression and expression of psoriatin.

TABLE 1

Examples	Sample (I)
		1	Control for LL-37 Gene expression
2	Positive control for LL-37 Gene expression, LPS (25 ↘ g/ml)
		3	Nicotinamide for LL-37 gene expression (1.22mg/ml)
4	Control for psoriatin gene expression
		5	Positive control for psoriatin gene expression LPS (25 ↘ g/ml)
6	Nicotinamide for psoriatin gene expression (1.22mg/ml)

。

Materials and procedures for measuring the expression of each gene are given below.

Material

Normal human neonatal epidermal primary keratinocytes (NHEK), Keratinocyte Growth Medium (KGM) and growth supplements, antibiotics (penicillin and streptomycin), Escherichia coli strain (ATCC strain 10536), Lipopolysaccharide (LPS) from Escherichia coli 055: B5 strain, 1 XP buffered saline, 10mM sodium phosphate buffer, nicotinamide, sterile cups (both ends open in the shape of a barrel, open end face)The product is 2.27cm²The rods are round tips made of hard Teflon (appendix 1), petrolatum component (appendix 2), psoriatin (S100a7) (CircuLex) and LL-37ELISA kit (Hycult), Macconkey agar medium, TSA medium (Unilever research report No.: BL 110086).

Stimulation of primary human skin keratinocytesHuman primary keratinocytes prepared from neonatal foreskin were obtained from (Lonza India) and cultured in serum-free keratinocyte growth medium containing defined growth supplements (Invitrogen). Keratinocytes were cultured in 12 and 24 well tissue culture plates (BD Falcon) and the cells were treated at 60-70% confluence. Keratinocyte stimulation was performed with growth supplements in KGM, and all experiments were performed between passage 3 to 5.

RNA isolation and quantitative real-time Polymerase Chain Reaction (PCR)

NHEK on 12-well plates (BD, Falcon) at 6X 10 per well⁴The individual cells were cultured. After 24 hours of incubation, 50% of the medium was replaced with fresh medium. On day 3, cells were treated with different concentrations of nicotinamide with fresh medium for 16-18 hours. Cells were harvested in RLT buffer (Qiagen) and samples were stored at-70 ℃ until used for RNA isolation.

Total RNA was isolated using the RNeasy Mini kit from Qiagen according to the manufacturer's instructions. Purity and RNA concentration were checked using a nanodrop (thermo scientific) instrument. The RNA samples were loaded on a 1% agarose gel and the quality of the extraction was observed using a UV transmission illuminator (Bangalore Genie, India). RNA samples were aliquoted and stored at-70 ℃. Aliquots of total RNA (250 to 500ng) were used to make cDNA by using the iScript cDNA synthesis kit (Bio-Rad, USA). The cDNA synthesis procedure was 5 minutes at 65 ℃ followed by 5 minutes at 25 ℃. cDNA synthesis was performed at 42 ℃ for 30 min, and finally denatured at 85 ℃ for 5 min, followed by 4 ℃ until removal.

Real-time PCR was performed using the SYBR green method using a thermal control Chromo4 machine (Bio-Rad, USA) according to the manufacturer's instructions (Bio-Rad, USA). By using a standardized PCR program (i.e.5 minutes at 94 ℃ followed by 50 "15 seconds at 94 ℃, 30 seconds at 60 ℃),30 second cycles at 72 ℃) in each reaction 5. mu.l of a 1:10 diluted cDNA sample and 1.5 picomoles of specific primers were used, and the results were obtained by using 2^-ΔΔCTAnd (4) analyzing by using the method.

Psoriatin and LL-37ELISA

Primary keratinocytes were seeded in 12-well plates (BD falcon). At 60 to 70% confluence, cells were treated with different concentrations of nicotinamide for 72 hours. After 72 hours of incubation, the cell culture supernatants were stored at-70 ℃ until used for ELISA. All ELISA reagents and samples were brought to room temperature before the assay. Cell culture supernatant samples were centrifuged at 5000rpm for 10 minutes before use. 100 ↘ l of an undiluted sample of cell culture supernatant was used to check the psoriatin levels by using the ELISA kit from CircuLex. Clinical samples were diluted to 1:25 in dilution buffer and 100 ↘ l of the diluted samples were used to examine psoriatin levels by ELISA. In the case of LL-37, 100 ↘ l of undiluted samples from in vitro as well as clinical samples were used to check the level of LL-37 by ELISA (Hycult Biotech).

Gene expression of psoriatin and LL-37AMP in keratinocytes was treated with nicotinamide for 18 hours. LPS (20. mu.g/ml) was used as a positive control to trigger the gene expression of psoriatin and LL-37AMP in primary keratinocytes after 18 hours was studied using the procedure given above. The results in terms of fold change are given in table 2 below.

TABLE 2

Examples	Sample (I)	Multiple change
			1	Control for LL-37 Gene expression	1.0
2	Positive control for LL-37 Gene expression, LPS (25 ↘ g/ml)	3.9
			3	Nicotinamide for LL-37 gene expression (1.22mg/ml)	2.4
4	Control for psoriatin gene expression	1.0
			5	Positive control for psoriatin gene expression LPS (25 ↘ g/ml)	2.3
6	Nicotinamide for psoriatin gene expression (1.22mg/ml)	1.1

。

The data in table 2 above show that even at very high concentrations (1.22mg/ml), nicotinamide does not induce psoriatin gene expression, but surprisingly, nicotinamide induces secretion of psoriatin AMP, as measured using ELISA techniques.

Examples 7 to 12: in vivo experiments with skin emulsions containing niacinamide to demonstrate skin induced cattle Secretion of pityristin and LL-37To confirm the findings from in vitro experiments, nicotinamide was tested in vivo on healthy human volunteersThe function of the drug is described. Volunteers were asked to apply a lotion with and without niacinamide (3%) on their forearms twice daily. After 7 days of application, spots (spots) were extracted in PBS and ELISA was performed to detect psoriatin and LL-37 AMP.

In vivo study procedure

Preparation of E.coli cultures

A glycerol stock of E.coli (10536) was inoculated in 30 ml of TSB medium and the culture incubated overnight at 37 ℃ in a shaking incubator. The overnight culture was subcultured on a TSA slant and incubated overnight at 37 ℃, followed by storage of the slant at 4 ℃ (once by 15 days, the slant was freshly prepared).

Coli cultures from the slants were subcultured on TSA plates and incubated overnight at 37 ℃. The overnight grown E.coli plate culture was suspended in 6 to 7 ml of sodium phosphate buffer (10 mM). The density of the culture was adjusted to 1OD using a spectrophotometer₆₂₀And used for clinical studies.

Cup scrubbing method of extraction

This technique is included in ASTM method E2752-10 (standard guidelines for evaluating residual effectiveness of antimicrobial agents). The cups and bars were made of Teflon and the area of the cups was 2.84cm². The cup is used to hold the buffer on the skin and the wand is used for scrubbing to better recover skin AMP and/or residual bacteria from the skin. The duration of the scrubbing was 1 minute. The extracted samples were collected in 1.5 ml microcentrifuge tubes for analysis (appendix 1).

Estimation of psoriatin and LL-37AMP by cup scrubbing and residual E.coli from human skin Counting

10 microliters of 1OD₆₂₀Coli cultures were applied 2.27cm above the labeled area on the forearm²Area (no spots applied by cream, base cream and niacinamide cream). The culture was spread evenly over each spot. After a contact time of 15 minutes, the sample was extracted in 1 ml PBS by cup scrubbing. Sample collectionCollected in sterile microcentrifuge tubes.

Of the extracted samples, 800 ↘ l were used to count residual E.coli by standard microbiological methods (100 ↘ l undiluted, -1 and-2 diluted samples were plated by plating on MacConkey agar plates). The remaining 200 ↘ l sample was used to analyze psoriatin and LL-37 levels by ELISA using a standardized kit. The pure sample was used to check the level of LL-37 in the sample. In the case of psoriatin, the samples were diluted to 1:25 in dilution buffer (which is provided with the kit) and 100 ↘ l of the diluted sample was used for analysis.

In vivo study design

1. Volunteers were asked to arrive at the study site every morning after bathing.

2. Marking 6.25cm on the inner forearm using a marking pen and ruler²Area (2.5 x 2.5 cm). Three areas were marked on the forearm, excluding the wrist (5 cm from the base of the palm). (if the mark becomes faint or erased, each volunteer is given a marking pen to mark the area).

3. An aliquot of 62.5mg of the formulation was weighed in a sterile container (35 mm plastic disc) and given to volunteers.

4. Volunteers were asked to apply the formulation in a circled spot on the forearm (62.5mg/6.25 cm)²Area). (the order of application is the base formulation followed by the formulation containing the active substance). The formulation was spread over the area for approximately 30 seconds each time.

5. After each formulation was applied, the fingers were wiped with sterile facial tissue.

6. A similar aliquot of 62.5mg of the formulation was weighed into a sterile 35 mm plastic petri dish, sealed with parafilm and given to each volunteer for application at night (before bedtime).

7. For the 7-day study, steps 3 to 6 were repeated for 7 days. In the case of the one-day study, the evaluation was performed on the following day.

8. On day 8, volunteers were asked to arrive at the study site in the morning without washing their forearms.

9. The volunteers' forearms were washed (by investigator) with non-antibacterial soap (Lux soap).

10. Excess water was removed by drying with a sterile facial tissue patted lightly.

11. Volunteers were asked to wait 6 hours without touching the forearm.

12. The templates were used to mark 2.27cm on each cream application spot²And 10 microliters to 1 × 10⁸To 1X 10⁹Coli 10536 culture per ml was added to each circular area and spread evenly.

13. After a contact time of 15 minutes, the E.coli was recovered by cup scrubbing using 1 ml of 1 XPBS. The duration of extraction was 1 minute.

14. Samples were analyzed for bacterial counts by plate spreading on MacConkey's agar.

The residual log of E.coli in the forearm region in the various experiments is summarized in tables 3 and 4 below:

table 3: log residual escherichia coli (n ═ 28) measured one day after application of the composition

Examples	Sample (I)	Multiple change
			7	Basic residual logarithm of Escherichia coli	4.21
8	Log residual on application of niacinamide free emulsion	3.44
			9	Log residual on application of 3% niacinamide containing emulsion	2.31

。

Table 4: log residual E.coli (n ═ 34) measured 7 days after application of the composition

Examples	Sample (I)	Multiple change
			10	Basic residual logarithm of Escherichia coli	4.41
11	Log residual on application of niacinamide free emulsion	3.56
			12	Log residual on application of 3% niacinamide containing emulsion	2.39

。

The data in table 3 above show that the composition comprising niacinamide is able to reduce bacteria even after one day of use, while table 4 shows that this effect is maintained for a long period of time (7 days of application).

Example 13: experiments to determine the type and amount of antimicrobial peptides (AMPs) secreted by NicotinamideThe following procedure was used to determine the AMP induced by niacinamide on keratinocytes.

1. Primary keratinocytes were seeded in 12-well plates with 1 ml KGM complete medium. (60,000 cells/well were seeded at passage 4).

2. Placing the plate in CO₂Incubate in incubator for 48 hours.

3. After 48 hours of incubation, cells were treated with and without nicotinamide at a concentration of 1 mg/ml in duplicate wells (fresh medium for treatment).

4. After 72 hours of incubation, the cell culture supernatants were transferred individually to 1.5 ml microcentrifuge tubes.

5. The sample was then passed through a 20kDa cut-off filter to remove high molecular weight proteins.

6. The eluted sample containing <20kDa protein was transferred to a 15 ml sterile centrifuge tube.

7. Subsequently, cold acetone (HPLC grade) was added to the eluted sample (1 ml sample: 4 ml acetone)

8. The tubes were transferred to-20 ℃ for 24 hours to precipitate the protein.

9. After 24 hours, the tubes were centrifuged at 14000g for 40 minutes at 4 ℃.

10. The supernatant was discarded and the protein particles were analyzed using mass spectrometry for proteins.

Data on the increased secretion levels of various AMPs are listed in table 5. The increased AMP secretion level is measured by the PSM value (peptide spectrum match score function), which is a relative measure of the abundance of peptides in the secreted proteome.

TABLE 5

The data in table 5 show that there are significantly higher levels of secretion of various AMPs due to the use of nicotinamide.

Examples 14 to 17: human volunteer study of the ability of the skin to defend itself against infection

Experiments were performed using the following protocol:

1. lux administration to volunteers^TMSoap was ready for use and required no other soap or moisturizer to be used on their forearms 7 days before the start of the study.

2. Volunteers were asked to apply Vaseline at different spots on the forearm^TMHealthy white base cream and Vaseline formulated with niacinamide (1%, 2% and 3%)^TMA healthy white cream.

3. Volunteers were asked to repeat step 1 twice a day for 1 day, after bathing in the morning and just before sleeping in the evening. Volunteers were asked not to wash the forearms after applying the formulation at night.

4. On day 2, forearms were washed with non-antibacterial soap bars by investigators and volunteers were asked to wait 6 hours under controlled conditions (24 ± 2 ℃ and 45% ± 5% RH).

5. After waiting 6 hours, -10 each spot was applied to the forearm, respectively⁶And (4) Escherichia coli. The contact time of E.coli on the skin was 15 minutes.

6. After 15 minutes, a sample was extracted from the forearm using the cup-stick method.

7. Coli were counted using standard microbiological methods.

Data for the E.coli counts for each treatment are summarized in Table 6.

TABLE 6

Examples	Sample (I)	Residual logarithm of Escherichia coli
			15	Control substance	4.3
16	1% of nicotinamide	3.5
			17	2% of nicotinamide	3.0
18	3% of nicotinamide	2.7

。

The data in table 6 show that the use of niacinamide enhances the inherent immunity of the skin against invading bacteria.

The present invention thus provides a new use of nicotinamide, heretofore unknown, which induces the secretion of antimicrobial peptides (AMPs) when applied on the external surface of the human body.

Claims

1. Use of niacinamide for the preparation of a personal care composition providing long-lasting protection against pathogens on a body surface, wherein said long-lasting protection lasts from 1 to 7 days after application of said composition.

2. The use as claimed in claim 1, wherein said niacinamide, when applied on the external surface of the human body, provides said long-lasting protection against germs to said personal care composition by inducing the secretion of antimicrobial peptides (AMPs) from keratinocytes.

3. Use as claimed in claim 1, wherein said composition comprises niacinamide in an amount of 0.1% to 5% by weight of the composition.

4. Use as claimed in any one of claims 1 to 3 for improving the immunity of the external surface.

5. The use as claimed in any one of claims 1 to 3 wherein the external surface comprises the skin, scalp or oral cavity.

6. Use as claimed in any one of claims 1 to 3 wherein the composition provides protection against dandruff.

7. The use as claimed in any one of claims 1 to 3, wherein the use is non-therapeutic use.